In our study, 39 of 70 patients (55.7%) who were admitted to hospital with various complaints were diagnosed GER by 24-hour pH monitoring. The distribution of the patients with GER by the initial symptoms at the time of admission was summarized in Table , .
GER occurs frequently during the first year of life with a peak incidence of 67% at 4 months of age. Also, at least one episode of reflux per day occurs in 50% of infants who are between the ages of birth and 3 months. GER is considered physiologic in early childhood period and disappears in the second year of life. The prevalence of GER was found to be 1.8-8.2% in epidemiological studies among children of 3-17 year of age groups [10
]. The frequency of GER was found as 37 to 52.3% in children who were performed by 24-hour esophageal pH-monitoring suspected GER disease [11
]. In our study GER was found to be 55.7% in patients. High frequency of GER was associated with the severity of the disease.
The frequency of GER was reported to be 25% to 80% among the children with recurring respiratory tract disease in several previous studies, [13
]. In our study, the respiratory system symptoms were the most frequently seen finding seen in the patients diagnosed with GER. Respiratory system symptoms were found in 24 cases of whom 18 from respiratory group and 6 from mixed group and it consisted of 60% of 39 patients. The association between GER and respiratory system has been known for a long time. Both esophagus and bronchial tree originated from the same primary nourishing path and were stimulated by the vagus nerve [14
]. Khoshoo et al. reported that they found a significant increase in GER incidence in children with asthma. Asthma was found in 50% to 60% of the children with GER [5
]. In our study, it was found that 24 out of 39 GER positive patients (61%) had chronic cough and non atopic asthma. Our results were found consistently with the literature.
Several mechanisms have been postulated by which GER might cause coughing. Aspiration of gastric juices containing acid, pepsin, bile acids and duodenal pancreatic enzymes, is considered to be an important mechanism in the etiology of reflux-related cough. Pharyngeal pH recording that demonstrated micro-aspiration of gastric contents into the pharynx favored this hypothesis [15
]. In the past, detection of lipid-laden macrophages in bronchoalveolar lavage fluid or sputum has been used as possible a marker for aspiration. Studies show that lipid-laden alveolar macrophages are present in 85% of children with chronic respiratory tract disorders and GER [16
]. A vagal reflex arc originating from the distal esophagus after either exposure to acid or esophageal distention can cause coughs [18
]. Acidification of the esophagus can activate local axonal reflexes which can cause inflammation in the airway. A study of Patterson et al. showed that the presence of acid in the esophagus in asthma and chronic cough patients causes releases of tachykinins such as substance P and neurokinin A into the lungs where they cause bronchoconstriction and airway micro vascular leakage [21
According to the given pH-meter monitoring parameters of GER positive patients in our study, we observed that the parameters were generally high in gastrointestinal and mixed groups. The reasons of high GER positivity in the mixed groups might be that of pH-meter parameters, the number of reflux in 24 hours, the number of reflux prolonged over 5 minutes in 24 hours, and the time interval when esophagus pH was under 4 were high in the mixed group in comparison with other groups. The children in the mixed group, who have both respiratory and gastrointestinal symptoms, are at higher risk of GER. In a study carried out with children population, it was denoted that patients with mixed respiratory and gastrointestinal symptoms had more severe disease than did patients with isolated respiratory disorders indicates that clinical symptoms are a good marker of reflux severity in children [21
]. In our study we found similar results.
The limitations of our study are the small number of the patients. The established incidence of GER in examined subgrups of patients is limited only to those with the acidic GER (pH-metry detected). In the remaining examined subjects who did not show the occurrence of acid reflux the presence of alkaline refluks should be suspected. Combined mulitichannel intraluminal impedance and pH measurement should be used. The examined group with mixed GER symptoms is numerically small. The severity of GER should be confirmed by application of diagnostic methods of pH-metry, gastroscopy (eosaphagitis?) and nature of the clinical symptoms observed in the patients. The study should be continued in the future, according to the above remarks, with MI Impedance and pH-metry application.